Recently, a service in which distribution terminal devices for distributing content data such as a piece of music are installed at a kiosk of a station, a convenience store and so forth, content data distributed from a host computer through a network are recorded on a magnetooptical disk such as an MD (Mini Disk) and the content data are distributed to audience is commercially available.
Because a large number of such distribution terminal devices are installed at various places, costs for sending maintenance staff to perform a regular maintenance of distribution terminal device become enormous.
In the distribution terminal device, its optical block for use in recording content data on the MD incorporates therein a semiconductor laser. In particular, since a lifetime of a semiconductor laser becomes considerably different depending upon frequency with which each distribution terminal device has been used and circumstances under which each distribution terminal device was installed, it is very difficult to predict a lifetime of a semiconductor laser. For this reason, in most cases, the maintenance staff visits a user (e.g., distributor, etc.) or a shop in which a distribution terminal device is installed to repair the distribution terminal device after the maintenance staff had received information on an occurrence of a trouble from the user or the shop.
When the maintenance of a distribution terminal device is to be carried out before the reliability of recorded content data by the semiconductor laser deteriorates, at present, the semiconductor laser should be exchanged earlier than the actual lifetime allowing for safety or the maintenance staff should regularly visit the place in which the distribution terminal device is installed, should inspect respective portions of the optical block and should confirm whether or not the semiconductor laser can be operated normally, which causes the maintenance costs to increase unavoidably.
Depending upon the place in which the distribution terminal device is installed, an inputted power source voltage becomes unstable due to some kinds of circumstances at a power source. For example, even though it can be confirmed that the power source voltage is stable when the distribution terminal device is installed, if electrical machinery and apparatus which consume a large electric power are installed near the distribution terminal device after the distribution terminal device had been installed, there is then the risk that the power source voltage of the distribution terminal device will become unstable.
When a power consumption within the same building is fluctuated depending upon a time period, it can be considered that the power source voltage is lowered during only a specific time period. If an enormous amount of content data is distributed from the host computer to the distribution terminal device in such time period, there is then a large possibility that an error will occur.